Revert of Move some sync/notifier to components/invalidation

sync/notifier/invalidation_state_tracker.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // An InvalidationStateTracker is an interface that handles persisting state
 // needed for invalidations. Currently, it is responsible for managing the
 // following information:
 // - Max version seen from the invalidation server to help dedupe invalidations.
 // - Bootstrap data for the invalidation client.
 // - Payloads and locally generated ack handles, to support local acking.
@@ skipping 14 matching lines @@
 #include "sync/notifier/unacked_invalidation_set.h"
 
 namespace base {
 class TaskRunner;
 }  // namespace base
 
 namespace syncer {
 
 class SYNC_EXPORT InvalidationStateTracker {
  public:
-  InvalidationStateTracker();
-  virtual ~InvalidationStateTracker();
+  InvalidationStateTracker() {}
+  virtual ~InvalidationStateTracker() {}
 
   // The per-client unique ID used to register the invalidation client with the
   // server.  This is used to squelch invalidation notifications that originate
   // from changes made by this client.  Setting the client ID clears all other
   // state.
   virtual void ClearAndSetNewClientId(const std::string& data) = 0;
   virtual std::string GetInvalidatorClientId() const = 0;
 
   // Used by invalidation::InvalidationClient for persistence. |data| is an
   // opaque blob that an invalidation client can use after a restart to
   // bootstrap itself. |data| is binary data (not valid UTF8, embedded nulls,
   // etc).
   virtual void SetBootstrapData(const std::string& data) = 0;
   virtual std::string GetBootstrapData() const = 0;
 
   // Used to store invalidations that have been acked to the server, but not yet
   // handled by our clients.  We store these invalidations on disk so we won't
   // lose them if we need to restart.
   virtual void SetSavedInvalidations(const UnackedInvalidationsMap& states) = 0;
   virtual UnackedInvalidationsMap GetSavedInvalidations() const = 0;
 
   // Erases invalidation versions, client ID, and state stored on disk.
   virtual void Clear() = 0;
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_NOTIFIER_INVALIDATION_STATE_TRACKER_H_